For me (American English) the meanings of "friendly" and "sincere" are more common than "realistic" or "sensible." In fact, I know people who are not very sensible, but they are very down to earth. They are friendly and honest. You could sit and chat about just about anything with a down to earth person. You feel really relaxed around him because he doesn't try to show off money, status, knowledge, etc. He's laid-back, up-front, and on the up and up.

It's unusual to include 'friendly' in the explanation. I wouldn't use it.

down to earth: practical / grounded in reality / doesn't have one's head in the clouds dreaming of outlandish things In american english, I've never gotten the sense that down to earth does encompasses the adjectives friendly, sincere, honest, and trustworthy, even though some are, that is not really the very definition of down to earth. So, in this case, I disagree with BRSwartz.

in our culture, down to earth means someone who is HUMBLE.

All good answers here. It would probably just boil down to the context of your conversation. =P 1.) The statement could mean that the person is "approachable" and "friendly", when pointing out to social behavior. 2.) The "realistic" meaning would probably be more applicable when talking about, say for instance, the ambitions of the person. 3.) Sarcasm can also make this statement into an insult. It really depends on what you're talking about. As for the difference between british and american meaning; I don't think there is. It would just be a difference in choice of words. So, that's a no. BRSwartz has a point because what mattters is how the people use the language: not just what's in the dictionary. You get what I mean.